Water-tube boiler.



No. 659,005. Patented Oct. 2, I900.

. THORNY'CROFT.

WATER TUBE BOILER.

(Application filed Nov. 24, 1897.)

(No Model.) 3 Sheets-Sheet l.

1 3 v IIIIIIIIQQ" l I I Patented Oct. 2, I900.

J. I. THOBNYCBOFT. WATER TUBE- BOILER. A immn filed 'Nov 24 1897) 3 Sheets-Shoat 2.

(No model.)

No. 659,005. Patented 0st. 2. I900.

J. l. THORNYCROFT.

WATER TU BE BOILER. (Application filed Nov. 24, 1897.)

(No Model.) 3 Sheets-Sheet 3.

lax-mums PETERS co FHrTH u UNTT STATES PATENT FFICE.

JOHN ISAAC THORNYCROFT, OF LONDON, ENGLAND.

WATER-TUBE BOILER.

SPECIFICATION formingpart of Letters Patent No. 659,005, dated October 2, 1900.

Application filed. November 24, 1897. serial No. 659,710. .lio model..-

To all whom it may concern.-

Be it known that I, JOHN ISAAC 'DHORNY? CROFT, a subject of the Queen of Great Britain and Ireland, residing at Chiswick, London, in the county of Middlesex, England, have invented certain, new'and useful Improvements in Water-Tube Boilers,(for which British Letters Patent No. 26,841 of 1896 have been granted to me,) of which the following is a specification.

In water-tube boilers as frequently constructed the gases generated by combustion rise from the fire and pass directly among the steam-generating tubes of the boiler. If the fire is.uneven by reason of inequalities in the thickness of the bed of fuel over the grate or from any other reason, so that the combustion is unequal, it will happen that the gases which pass from the fire among the tubes are different in combustible quality. It will be readily seen, therefore, that in such cases the combustion of the gases among the tubes will vary very considerably according to the quality of these gases, and the tubes in different parts of the boiler will therefore receive different degrees of heat. It frequently occurs that at or near the base of the funnel or up-take' a very active combustion takes place with a resultinggreat loss of heat which should be utilized in the generation of steam in the tubes.

My invention has for one object to produce a boiler in which the gases shall be collected from all parts of the fire andintimately mixed and averaged in combustible quality before they pass into the spaces among the tubes, thereby equalizing the combustion among the tubes and preventing the waste and loss of heat arisingfrom a combustion of varying activity in difierent parts of the tubes.

A further object of the invention is to produce a Water-tube boiler in which the move ment of the gases is controlled and the gases are distributed equally to all the spaces between the tubes.

With these and other objects in view my invention consists in certain constructions,

like numerals of reference indicate the same parts, I have shown the invention as applied to two .types of boilers, one being the type commonly known as the Speedy type and the other commonly known as the Daring yp s Figure 1 shows in cross-section a portion of a boiler of the Speedy type embodying my invention. Fig. 2 shows a similar View of a boiler of the Daring type, also embodying my invention. Fig. 3 is a longitudinal vertical section showing the construction as it would appear if. the section were taken on either theline 00 a; of Fig. l or the line no at" of Fig. 2. Fig. 3 is a sectional plan on the liney y of Fig. 1. Figs. 3 and 3 are diagrams illustrating modified forms. Figs. 4, 5, and 6 are views similar to Figs. 1 2, and 3, respectively, but showing a modified construction. v Figs. 7, 8, and 9 .are also views similar to Figs. 1, 2, and 3, respectively, and showing another modification.

In the drawings it is to be noted that the right-hand portion of Fig. 1 corresponds to a section on the line a ct of Fig. 3, and the lefthand portion of Fig. 2 also corresponds to a section on the same line. "The left-hand portion of Fig. 1 corresponds to a section on the line b b of Fig. 3, and the same is true of the right-hand portion of Fig. 2.

' Referring to the construction shown in Figs. 1 to 3, inclusive, 1 indicates the ordinary fire-grate, having the usual combustionchamber above it. This combustion-chamber is provided with a roof or partition, which may be formed in various ways. In the constructions shown in the figures referred to this roof is formed by two partitions 3 and 4, composed of suitable refractory material, such as fire-brick, and extending from the front and rear walls of the combustion-chamber. These partitions lie on different levels, and thus a narrow passage or opening 5 is formed between them. the gases from all parts of the fire will be collected by these partitions and caused to pass through this narrow opening 5.

, Above the roof or partitions before referred to is located a secondary mixing and combustion chamber, into which the gases are de- It is apparent that livered from the narrow opening 5, before retion shown in the drawings the walls of this secondary combustion-chamber are formed by rows of tubes. It will be seen that the tubes 2 which connect the water-chambers 9 and 10, which are located at the sides of the fire-boxes, with the upper steam and water chamber are inclined and juxtaposed so as to form the side walls of the secondary mixing-chamber, the bottom of which is formed by the roof of the primary combustion-chamher 3.

It will be apparent that as the gases are collected from the parts of the fire and brought together and delivered through the narrow opening 5, before referred to, to the secondary chamber, into which they expand, they will be intimately mixed and averaged in combustiblequality. Combustion isaccordingly facilitated orpromotedin the secondarychamher, and the products which leave this chamber and pass among the various tubes will be of a more-nearly equal quality and temperature than if they had passed directly from the fire to the spaces among the tubes. For instance, it might happen that the gases collected from that part of the fire which is nearest the feeding-door would be totally different in combustible character from those arising from the end of the fire in the r 1.1 of the fire-box. If now these gases should pass direct to the tubes in the condition in which they rise from the different parts of the fire, it will be seen that different degrees of heat would be generated in the tubes nearestthese parts of the fire.

By the improvement specified the gases from all parts of the fire are brought together and made to meet in passing through the narrow opening referred to and in the secondary mixing-chamber. As the gases leave this chamber, therefore, they will be comparativelyeven in quality, and the result, as will be apparent, is that a much more even degree of heat is obtained among the tubes.

The roof or partition which separates the primary combustion-chamber from the secondary mixing and combustion chamber may be formed in various ways. In Figs. 1, 2, and 3, for instance, as before described, I have shown two half-roofs extending, respectively, from the sides and front and the sides and rear of the fire-box and located at different levels,so as to form the narrow opening 5, referred to.

Figs. 3 and 3 show constructions in which more than partitions are used, forming more than one narrow opening. While these forms are shown as illustrating some modifications, it is apparent that the construction may be modified in many other ways, the purpose of the invention being to so separate the primary combustion-chamber from the secondary mixing and combustion chamber as to cause the gases to pass from all parts of the fire in the primary combustion-chamber to the secondary or mixing chamber through one or more narrow openings, thereby becoming mixed and averaged. It is also ap parent that the partitions 3 4., before referred to, may be formed from tubes or from a combination of tubes and refractory material. In Figs. 4, 5, and 6 I have shown an arrangement in which the tubes 2, which connect the steam and water generator with the water-tubes, pass under the upper partition 4, so that in this case the partition may be said to be constructed from a combination of tubes and refractory material. It is apparent that the tubes might be caused to pass around the lower partition 3 as well as the upper partition 4; but this modification being obvious it is not illustrated.

In Figs. 7, 8, and 9 I have shown both partitions as formed entirely from tubes. The construction is obvious from the drawings and need not, therefore, be further described.

\Vhile the tubes which form the walls of the secondary mixing or combustion chamber may be arranged in various ways, itis desirable in order to gain as much heatingspace as possible that the tubes be arranged to form inner and outer close walls, between which are situated other tubes. Such a construction is shown in Figs. 2, 3, and 3. The inner row of tubes forms a close wall 2 and the outer row of tubes another close wall 2". These close walls form between them a fine 7, into which the gases pass from the secondary mixing and combustion chamber. In this flue 7 are located the remaining tubes 2.

While the tubes forming the inner close wall may be arranged in various ways to permit the passage of the gasesfrom the secondary chamber into the flue 7, I preferably arrange them so as to leave openings 6 between the ends of the tubes, so that the gases from all parts of the secondary chamber will pass downward and outward through these openings and then upward through the fine 7. The gases may be led out from the fine 7 in various ways. I prefer, however, to arrange the tubes so as to form opening 6 between the upperends of the tubes which form the outer wall 2 through which the gases may pass and escape to the chimney or uptake. By this construction a much greater heating-surface can be obtained without materially increasing the size of the boiler. The two groups of the tubes at the inner side of the firegrate are arranged to form gas-exit fines, as described in the specification of Letters Patent No. 452,401, granted to me May 19, 1891.

It will be apparent that the hot gases by reason of their inertia will tend to continue to move in the same direction as they had when they left the narrow openings 5, which is the source of communication between the two chambers. The result of this tendency will be that the tubes directly in this line of movement will be apt to receive a greater amount of gases, and therefore a greater degree of heat, than the other tubes. In order to overcome this tendency and to distribute the hot gases as uniformly as possible among ICS the tubes 2 after they have passed through the openings 5, the tubes which form the inner walls of the chamber and which are bent, as before described, to form the exit-openings 6 are preferably so bent as to make these exit-openingsfi of varying size, those of the exit-openings which are directly in line with the movement of the gases before referred to being made smaller than the openings between the other tubes. To effect this result in the construction of boilers shown in the drawings, the openings between the lower ends of the tubes 2 atthe front portion of the boiler, toward which when the partitions are arranged as shown the hot gases will tend to move after passing throughthe openings 5,are made smaller, as shown at 6, (see the left-hand side of Fig. 1 and the right-hand side of Fig. 2,) than the openings shown at 6 between the lower ends of the tubes at the rear portion'of the boiler.

It is apparent not only that the arrangement and construction of the partitions or roofs which act collect the gases from the parts of the fire and distribute them through the inner opening or openings into the secondary mixing-chamber may be varied within wide limits, but also that the arrangement of tubes which form the walls of the secondary chamber may also be varied widely. The invention is not, therefore, to be limited to. the specific means shown and described for forming either the gas-collecting devices or the walls of the secondary chamber, but it is to be considered as generic in its nature, and

therefore the means for carrying it into operation may be widely varied without departing from the spirit and scope of the invention.

I am aware that water-tube boilers have been heretofore constructed in which the hot gases pass from the fire through narrow open ings either to the spaces among the tubes or to chambers from which they pass to the spaces among the tubes. My invention, however, differs Widely from such constructions in that, so far asI am aware, no attempt is made in them to collect and bring together the gases from all parts of the fire and then deliver them to a secondary combustion and mixing chamber, in which they are mixed and averaged in combustible quality before passing to the spaces among the tubes.

What I claim is-- 1. In a water-tube boiler the combination with a primary combustion-chamber, of a secondary combustion and mixing chamber having rows of tubes around it, and means for collecting the gases fromall parts of the fire in the primary combustion-chamber and delivering them to the secondary combustionchamber whereby the gases are mixed and averaged in combustible quality before passing to the spaces among the tubes, substantially as described.

2. In a water-tube boiler, the combination with a primary combustion-chamber, of a secondary mixing and combustion chamber communicating with the primary combustion ber and delivering them through the small opening. into the mixing-chamber whereby the gases are mixed before they reach the spaces among the tubes, substantially as described.

3. In a water-tube boiler, the combination with a primary combustion-chamber, of a roof located thereover whereby thegases from the diiferent parts of the fire are collected,a secondary mixing and combustion chamber located above the roof and communicating with the first combustion-chamber by a narrow opening, a wall of tubes inclosing the secondary mixing and combustion chamber. whereby the gases are mixed and averaged in combustible quality and combustion facilitated before the gases reach the spaces'among the tubes, substantially as described.

4. In a water-tube boiler, the combination with a combustion-chamber, of a roof located thereover and having its parts on different levels whereby a narrow opening is formed between the different parts of the roof, a secondary mixing and combustion chamber located above the roof, and rows of tubes surrounding said chambers whereby the gases are'collected from all parts of the fire and averaged in combustible quality and combos tion facilitated before the gases reach the spaces among the tubes, substantially as described.

5. In a water-tube boiler, the combination with a combustion-chamber, of a secondary mixing and combustion chamber the bottom and ,walls of which are composed of tubes and which communicates with the first combustion-chamber by a narrow opening whereby gases are collected from all parts of the fire and mixed and averaged in combustible quality and combustion is facilitated before the gases reach the spaces between the tubes which form the walls of the chamber, substantially as described.

- 6. In a water-tube boiler, the combination with a combustion-chamber, of a roof for said chamber formed by partitions of tubes which are arranged at difierent levels, the partitions being arranged to form a narrow opening between them, a secondary combustion-chamber. located above the roof and inclosed by walls of tubes whereby gases are collected from all parts of the fire and mixed and averaged in combustible quality and combustion is'facilitated before the gases reach the spaces between -the tubes which form the walls of the chamber, substantially as described.

7. In a water-tube boiler, the combination with a primary combustion-chamber, of a secondary mixing and combustion chamber located above the primary combustion-chamber and communicating therewith by a narrow opening, a wall of tubes surrounding the secondary chamber, these tubes being spaced apart at one end to allow the passage of the mixed gases therethrough and a second wall of tubes outside the first wall and forming a smoke-flue, substantially as described.

8 In a water-tube boiler, the combination with a primary combustion -chamber, of a secondary mixing and combustion chamber communicating with the primary combustionchamber by a narrow opening, a wall of tubes surrounding the secondary chamber, these tubes being spaced apart at one end to allow the passage of the mixed gases therethrough and a second wall of tubes outside the first wall and forming a smoke-flue, and additional tubes located in the flue, substantially as described.

9. In a water-tube boiler, the combination with a combustion-chamber, of a row of tubes forming the walls thereof, the said tubes being bent at their ends to provide spaces of varying size, the spaces through which the In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JOHN ISAAC THORNYOROFT. Witnesses:

EDMUND S. SNEWIN, WM. 0. BROWN. 

